Gramophone-record.



G. L. RO'LHJJD'Il` GBAMOPEONE RECORD.

.wynouxon Hmm DEG. ze, 1911.

rammed Dec. 1o, 1912.`

CORNELIUS LEONI-IARD ROTIIEUIT, OF WALHEIM, NEAR AACHEN, GERMANY.

GBAMOPHO'NE-RECORD.

To all whom it 'may concern:

Be it known that I, CORNELIUS LEON HARD ROTHEUDT, a subject of the Emperor of Germany, residino at .Wlalheinn near Aachen, Germany, have invented certain 'Improvements in Gramopllone-Records, of which the following is a specification.

l/Vhen it is desired to play a gramophone record several times in succession, the stylus must each time be lifted and transferred from one endotl the record groove to the other, the play being meanwhile interrupted. This is of great disadvantage particularly when marches and dances are to be repeated which repetition ought to be obtained without noticeable interruption in the play. This drawback is remedied by the present invention according to which the groove of' a gramophone disk is made endless, the ends of the record groove being joined by a return groove carried in a parabolic curveacross the turns of said record groove. The

direction of the curve is naturally dependent upon the direction -in which the disk turns and its form should be such as to guide the stylus with as little resistance as possible. Having once been started inv 'the 'direction of the return groove, the stylus is easily guided through the same, and ,the part of the groove which crosses the turns of thel record groove can therefore be narrowed suicientl, for preventing it having a detrimental e ect on the record. The in- Specication of Letters Patent.

Patented Dec.10. 1912.

Application filed IDecenibei` 26, 1911. Serial No. 667,896.`

terruption caused to the music while the stylus passes through the return-groove vwill hardly be noticeable.

' The invention is illustrated by way of example in the accompanying drawing by a plan of the improved gramophone disk.

In said drawings (L is the disk and b the spiral groove which contains the record. The ends of the groove are joined by the return groove c which is carried'in a parabolic curve across the turns ofthe groove Z).

The record is started in the m'dinarymanner, and the stylus is automatically returned by the groove c to the starting end of the groove b so as to repeat the piece as long as the disk is kept in motion.

1. A gramophone disk comprising a return groove carried across the tuns of the record groove and connecting the ends of the latter so as to return the sty-lusautomat-ically toits starting position, substantially as set forth.

2. A gramophone disk comprising a return groove carried in a parabolic curve across the turns of the record groove and 

